WhenToBird

Mergus merganser · Anatidae

When Do Common Mergansers Arrive in Indiana?

Adult female Common Merganser
Photo: Christoph Moning, CC BY 4.0 via iNaturalist

Common Mergansers are winter birds in Indiana: the first arrive in late November, they are common by early December, peak in early February (4.0% of checklists), and most are gone by mid March.

When to look

First arrivalsNov 22-30late November
Common byDec 1-7early December
PeakFeb 1-7early February
Most gone byMar 15-21mid March

Best: early February. First arrivals late November; most are gone by mid March. Peak: on about 4.0% of Indiana checklists.

  1. Janpeak season
  2. Febpeak season
  3. Marpeak season
  4. Apruncommon
  5. Maynot usually seen
  6. Junnot usually seen
  7. Julnot usually seen
  8. Augnot usually seen
  9. Sepnot usually seen
  10. Octrare
  11. Novuncommon
  12. Deccommon

Darker months: more checklists report it. Outlined: peak month.

0%2%4%6%Jan 1-7: 2.4% of 18123 checklistsJan 8-14: 2.8% of 12006 checklistsJan 15-21: 3.7% of 12403 checklistsJan 22-31: 4.0% of 16181 checklistsFeb 1-7: 4.2% of 12546 checklistsFeb 8-14: 3.8% of 14250 checklistsFeb 15-21: 3.3% of 18077 checklistsFeb 22-28: 4.6% of 13590 checklistsMar 1-7: 4.0% of 14545 checklistsMar 8-14: 3.0% of 14594 checklistsMar 15-21: 2.0% of 13894 checklistsMar 22-31: 1.2% of 22400 checklistsApr 1-7: 0.6% of 18069 checklistsApr 8-14: 0.1% of 19579 checklistsApr 15-21: 0.1% of 19518 checklistsApr 22-30: 0.1% of 30544 checklistsMay 1-7: 0.1% of 28430 checklistsMay 8-14: 0.1% of 30624 checklistsMay 15-21: 0.1% of 22920 checklistsMay 22-31: 0.1% of 21234 checklistsJun 1-7: 0.1% of 12279 checklistsJun 8-14: 0% of 10904 checklistsJun 15-21: 0.1% of 9488 checklistsJun 22-30: 0% of 11362 checklistsJul 1-7: 0.1% of 9947 checklistsJul 8-14: 0% of 9585 checklistsJul 15-21: 0% of 8929 checklistsJul 22-31: 0.1% of 12639 checklistsAug 1-7: 0% of 9528 checklistsAug 8-14: 0.1% of 9451 checklistsAug 15-21: 0% of 9442 checklistsAug 22-31: 0.1% of 14969 checklistsSep 1-7: 0.1% of 12628 checklistsSep 8-14: 0.1% of 11793 checklistsSep 15-21: 0.1% of 11396 checklistsSep 22-30: 0% of 14203 checklistsOct 1-7: 0.1% of 11365 checklistsOct 8-14: 0% of 12092 checklistsOct 15-21: 0.1% of 10440 checklistsOct 22-31: 0.3% of 13883 checklistsNov 1-7: 0.2% of 10476 checklistsNov 8-14: 0.6% of 9776 checklistsNov 15-21: 0.8% of 9035 checklistsNov 22-30: 1.1% of 12547 checklistsDec 1-7: 1.6% of 9078 checklistsDec 8-14: 2.1% of 8732 checklistsDec 15-21: 1.4% of 11024 checklistsDec 22-31: 2.1% of 15432 checklistsJanFebMarAprMayJunJulAugSepOctNovDec
Share of complete checklists reporting it, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.

Frequency is the share of complete checklists in Indiana that listed the bird, 2016–2025. It is not a head count, and it follows where and when people go birding. How to read it.

JanFebMarAprMayJunJulAugSepOctNovDec
today
Second week of November

Each county is shaded by the share of complete checklists there that listed the bird, blended with the weeks either side. Darker is more often. It follows where people watch birds, not how many birds there are. How to read it.

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Where in Indiana

Best counties

Share of checklists at the peak
  1. Lake CountyBest late January · 546 checklists that week, 22,199 in all19%
  2. Parke CountyBest late February · 17 checklists that week, 1,527 in all19%
  3. Sullivan CountyBest mid January · 101 checklists that week, 4,018 in all16%
  4. Warren CountyBest the second week of February · 11 checklists that week, 458 in all15%
  5. Vermillion CountyBest mid January · 22 checklists that week, 772 in all13%
  6. Porter CountyBest late January · 622 checklists that week, 29,087 in all13%

Best spots

Share of checklists at the peak
  1. Saint Josephs LakeSt. Joseph County, best late January · 64 checklists that week, 1,064 in all56%
  2. Greene-Sullivan State ForestSullivan County, best late January · 27 checklists that week, 272 in all55%
  3. Eagle Creek Park (southeast 2)Marion County, best late February · 29 checklists that week, 1,049 in all46%

Busy spots report more of everything; compare the checklist counts before you drive anywhere.

Best time of day

In Indiana, the Common Merganser is most often listed on checklists started between 2 and 4 pm (1.5% of those checklists).

0%0.5%1%1.5%12 am: too few checklists (240) to judge1 am: too few checklists (231) to judge2 am: too few checklists (222) to judge3 am: too few checklists (202) to judge4 am: too few checklists (674) to judge5 am: too few checklists (4329) to judge6 am: 0.4% of 20589 checklists7 am: 0.6% of 58470 checklists8 am: 0.8% of 86931 checklists9 am: 1.0% of 78239 checklists10 am: 1.1% of 66080 checklists11 am: 1.2% of 54904 checklists12 pm: 1.3% of 47610 checklists1 pm: 1.4% of 44814 checklists2 pm: 1.5% of 43790 checklists3 pm: 1.4% of 42983 checklists4 pm: 1.4% of 45349 checklists5 pm: 1.1% of 35993 checklists6 pm: 0.4% of 26447 checklists7 pm: 0.1% of 17740 checklists8 pm: too few checklists (7603) to judge9 pm: too few checklists (1721) to judge10 pm: too few checklists (517) to judge11 pm: too few checklists (272) to judge12a3a6a9a12p3p6p9p
Share of checklists started in each local hour that reported it. It reflects when people go birding as well as when birds are active. Grey hours have too few checklists (under 2% of the state’s, or under 200) to judge.
Week-by-week table
MonthDays 1-78-1415-2122-end
January2.4%2.8%3.7%4.0%
February4.2%3.8%3.3%4.6%
March4.0%3.0%2.0%1.2%
April0.6%0.1%0.1%0.1%
May0.1%0.1%0.1%0.1%
June0.1%0%0.1%0%
July0.1%0%0%0.1%
August0%0.1%0%0.1%
September0.1%0.1%0.1%0%
October0.1%0%0.1%0.3%
November0.2%0.6%0.8%1.1%
December1.6%2.1%1.4%2.1%

Neighboring states

  • Illinois: arrives the second week of November, 2 weeks earlier than Indiana
  • Ohio: arrives late October, 4 weeks earlier than Indiana
  • Michigan: arrives the second week of September, 10 weeks earlier than Indiana
  • Wisconsin: arrives mid September, 9 weeks earlier than Indiana

Common questions

When do Common Mergansers arrive in Indiana?
Common Mergansers are winter birds in Indiana: the first arrive in late November, they are common by early December, peak in early February (4.0% of checklists), and most are gone by mid March.
When do Common Mergansers leave Indiana?
Most Common Mergansers have left Indiana by mid March, when reports fall below half their usual rate. Stragglers are still reported until late March.
When is the best time to see a Common Merganser in Indiana?
The Common Merganser is reported most often in early February, on about 4.0% of Indiana checklists.
Where in Indiana are Common Mergansers seen most often?
By county, Lake County, Parke County, and Sullivan County have the highest peak reporting rates for the Common Merganser (counties with at least 200 checklists).